Canal lock system

ABSTRACT

A canal lock system for recirculating water between a reservoir and canal lock that uses air pressure to change the water level in the canal lock. The canal lock system comprises at least one canal lock, at least one reservoir for holding recirculated water connected to the bottom of the at least one canal lock, and at least one air pump connected to the at least one reservoir for pressurizing the at least one reservoir with air to force the water into the at least one lock to thereby change a first water level in the at least one canal lock to a higher second water level, wherein the at least one reservoir maintains a constant volume and wherein the at least one reservoir is depressurized to thereby change the second water level to a lower third water level.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application makes reference to and claims the priority date of the following co-pending U.S. Provisional Patent Application: U.S. Provisional Patent Application No. 60/822,309, entitled “Canal Lock System,” filed Aug. 14, 2006. The entire disclosure and contents of the above application is hereby incorporated by reference.

BACKGROUND

1. Field of the Invention

The present invention generally relates to a canal lock system for raising or lowering a ship in a canal lock from one water level to another water level by pressurizing a reservoir holding recirculating water connected to the canal lock with air to raise the water level in the canal lock, and depressurizing the reservoir to lower the water level in the canal lock. The present invention also generally relates to a method for operating the canal lock system.

2. Related Art

Canals are widely used to raise and lower ships from one level to another level, thereby allowing a ship to cross over land. The ship is raised and lowered using a flight of canal locks that are fed from a source, such as a reservoir or natural lake, using gravity to pull the water from highest point to lowest point, i.e. sea-level. As a result, each time a ship passes through the canal locks water is spilled from the source and into the ocean. For example, in the Panama Canal it is estimated that over 50 million gallons of fresh water from a natural lake is dumped into the ocean for every ship that moves through the canal locks. In addition, to the waste of water, such conventional systems also do not prevent contamination or species interchange. Contamination, or salt water intrusion, occurs when the salt water of the ocean mixes with the fresh water of the natural source and surrounding rivers, lakes and estuaries. Also plants and animals may interchange, in which species on one part of the canal may invade the species on another part of the canal.

In some canals, the water may be pumped between locks instead of using gravity. However, water pumps are expensive to build and maintain. Further, water pumps do not eliminate the problems with the waste of fresh water, contamination, or species interchange.

SUMMARY

According to a first broad aspect of the present invention there is provided a canal lock system comprising: at least one canal lock having a bottom and a first water level; at least one reservoir for holding recirculated water connected to the bottom of the at least one canal lock; and at least one air pump connected to the at least one reservoir for pressurizing the at least one reservoir with air to force the water into the at least one lock to thereby change the first water level in the at least one canal lock to a higher second water level, wherein the at least one reservoir maintains a constant volume and wherein the at least one reservoir is depressurized to receive the water from the at least one lock to thereby change the second water level to a lower third water level.

According to a second broad aspect of the present invention there is provided a canal lock system comprising: at least one canal lock; at least one reservoir that holds recirculated water; means for pressurizing the at least one reservoir with air to force the water into the at least one canal lock to thereby change a first water level to a higher second water level in the at least one lock; and means for recirculating the water from the at least one canal lock to the at least one reservoir to thereby change the second water level to the first water level, wherein the at least one reservoir maintains a constant volume.

According to a third broad aspect of the present invention there is provided a method for operating a canal lock system comprising the followings steps: pressurizing at least one reservoir that holds recirculating water with air to force the water into at least one canal lock to thereby change a first water level to a higher second level in the at least one lock; and recirculating the water from the at least one canal lock to the at least one reservoir to thereby change the second water level to the first water level, wherein the at least one reservoir maintains a constant volume.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a canal lock system according to one embodiment of the present invention;

FIG. 2 is a perspective view of a plurality of canal locks according to one embodiment of the present invention;

FIG. 3A is a cross-sectional view taken along line A-A of FIG. 2;

FIG. 3B is a cross-sectional view taken along line B-B of FIG. 2;

FIG. 4A is a cross-sectional view similar to that of FIG. 3A of a ship being lowered in a canal lock according to one embodiment of the present invention;

FIG. 4B is a cross-sectional view similar to that of FIG. 3B of the ship being lowered in a canal lock according to one embodiment of the present invention;

FIG. 5A is a cross-sectional view similar to that of FIGS. 4A of a ship being raised canal lock according to one embodiment of the present invention;

FIG. 5B is a cross-sectional view similar to that of FIG. 4B of the ship being raised in a canal lock according to one embodiment of the present invention;

FIG. 6A is a cross-sectional view similar to that of FIG. 5A of a ship exiting a raised canal lock according to one embodiment of the present invention;

FIG. 6B is a cross-sectional view similar to that of FIG. 5B of a ship exiting a raised canal lock according to one embodiment of the present invention;

FIG. 7A is a cross-sectional view similar to that of FIG. 6A of an empty raised canal lock according to one embodiment of the present invention; and

FIG. 7B is a cross-sectional view similar to that of FIG. 6B of the empty raised canal lock according to one embodiment of the present invention.

DETAILED DESCRIPTION

The embodiments of the present invention provide a canal lock system that raises and lowers the water in at least one canal lock having a bottom using air pressure. The air pressure may be supplied by at least one air pump. The air pump pressurizes the at least one reservoir with air to force water out of at least one reservoir, where each reservoir is connected to the bottom of each canal lock to thereby raise the water level in each canal lock. Air pressure is released to depressurize the at least one reservoir to receive water from each canal lock to thereby lower the water level in each canal lock. When the water level in each canal lock is raised or lowered, a ship in the canal lock is also raised or lowered. Such embodiments provide a canal lock system that recirculates the water from the at least one reservoir to each canal lock. By recirculating the water from the at least one reservoir, the amount of water wasted is minimized as well as reducing contamination and species interchange that may occur with other canal lock systems.

FIG. 1 provides a schematic diagram of a canal lock system 100 according to one embodiment of the present invention. Canal lock system 100 comprises a controller 102 that operates air pump 104 and driver 106. Air pump 104 pressurizes a reservoir 108 with air such that the water in reservoir 108 is forced through culvert 110 and into canal lock 114. Driver 106 operates or regulates water valve 120 to open culvert 110 when air pump 104 pressurizes reservoir 108 with air. Driver 106 may also operate water valve 120 to close culvert 110 when no ship is in canal lock 114 and when the water level in canal lock 114 is raised. Driver 106 may also operate air valve 122 to vent (depressurize) the pressurized reservoir 108 when lowering the water level in canal lock 114. Driver 106 closes air valve 122 to create an air tight seal when pressurizing reservoir 108 with air. Canal lock system 100 thus recirculates water between reservoir 108 and canal lock 114 during the raising or lowering of the water level in canal lock 114.

As described in the various embodiments below, depending on canal lock system 100, the various components shown in FIG. 1 may be employed in different configurations.

Controller 102 may be an electronic device, such as a computer, that employs a computer program or programmable logic. Controller 102 may also be connected to one or more sensors in canal lock 114. These sensors may provide a variety of information relating to the height of the water level, when are the gates open, the speed of the ship passing through, etc. One controller 102 may further control one or more locks, for example, in a flight of locks or along a canal. As used herein, the term “flight of locks” refers to a series of locks in close-enough proximity to be identified as a separate group of locks.

Air pump 114 may be any suitable pump capable of pressurizing air (or similar gas) into reservoir 108. As used herein, the term “pressurizing air” refers to increasing the air (or similar gas) pressure such that the air (or similar gas) pressure is greater than the normal atmospheric pressure. As used herein, the term “depressurizing air” refers to decreasing the air (or similar gas) pressure to approximately the normal atmospheric pressure. Air pump 114 may refer generally to the entire air pump system, including the motor, may be a piston air pump, diaphragm compressor air pump, vacuum air pump, etc. In some embodiments, a plurality of air pumps 114 may be used to pressurize a single reservoir 108 with air. In alternative embodiments, one air pump 114 may be connected to one or more reservoirs 108.

Driver 106 may be any suitable device capable of applying a force, such as an electrical motor, mechanical engine, hydraulic machinery, etc., that is able to open and close water valve 120 and air valve 122. In some embodiments, driver 106 may comprise one or more drivers that each separately operate the water valve 120 and air valve 122. In alternative embodiments and depending on the type of valve used, a driver may be optional or unnecessary. In such alternative embodiments, controller 102 may operate valves 120 and/or 122 when not operated by a driver.

Water valve 120 (used to control the flow of water between canal lock 114 and reservoir 108) and air valve 122 (used to control the pressurization and depressurization of reservoir 108) may be any type of valve including stop valves, such as global, gate, butterfly or ball valves, etc., or check valves, such as stopcheck, lift, relief, spring load, pressure-reducing or priority valves, etc. It should be understood that different types of valves may be used for water valve 120 and air valve 122. In addition, water valve 120 and air valve 122 may comprise one or more individual valves that form a valve system.

Reservoir 108 may be an underground water storage tank or basin. In some embodiments, reservoir 108 may be partially buried. In either situation, reservoir 108 has sufficient strength to hold recirculated water used for raising or lowering the water level of canal lock 114 and to withstand the pressure created by air pump 104. This allows reservoir 108 to maintain a constant volume, i.e., minimal or no change in the volume of reservoir 108. Further, no walls are actuated or moved to cause the pressure to increase inside reservoir. In one embodiment, reservoir 108 may be completely enclosed so that when air valve 122 is closed, reservoir 108 is substantially air tight. Although one reservoir 108 is shown for canal lock 114, it should be understood that a plurality of reservoirs 108 may be used for canal lock 114. Each of the plurality of reservoirs may have an air pump 104 and a culvert 110. In alternative embodiments, one reservoir 108 may service a plurality of canal locks 114 and have a different culvert 110 for each canal lock 114.

When a plurality of reservoirs 108 or culverts 110 are used in some embodiments, culverts 110 may be interconnected through a manifold. Also there may be an additional piping that connects each of the plurality of reservoirs 108.

Referring now to FIG. 2, which illustrates a perspective view of an exemplary flight of canal locks 214 and 216 that use an embodiment of the canal lock system 200 of the present invention. Ship 212 is shown traveling in channel 230 and will pass through sequentially through gate 232, canal lock 214, gate 234, canal lock 216 and gate 236 to enter elevated channel 238. For each of adjacent canal locks 214 and 216 there is shown an air pump 204 and a vent shaft 240. Air pump 204 pressurizes an underground reservoir (not shown) with air to force water from the reservoir into canal lock 214 to thereby raise the water level in canal lock 214. To lower the water level the pressurized air is released to depressurize the reservoir through vent shaft 240.

Although two locks are shown in FIG. 2, embodiments of the present invention may be used with a single lock, or a flight of locks, e.g., comprising a series of locks.

Gates 232, 234 and 236 may comprise a pair of doors which open and close. Gates 232, 234 and 236 may be any type of gate suitable for a canal lock, such as a miter gate, rolling gate, other similar type of gates, etc. When ship 212 is in canal lock 214, gates 232 and 234 may be closed to confine ship 212 in canal lock 214. Similarly, when ship 212 is in canal lock 216, gates 234 and 236 may be closed to confine ship 212 in canal lock 216.

As used herein ship 212 may refer to all types of sea-going watercraft including, without limitation, boats, barges, rafts, vessels, tankers, transporters, etc. Ship 212 may be without limitation of any type of propulsion, size, length, or deck. For example, ship 212 may refer to a Panamax ship or a Post-Panamax ship.

FIGS. 3A through 7B show various exemplary stages of a ship 212 moving through canal lock 214 of canal lock system 200 of FIG. 2 and using embodiments of the present invention. FIGS. 3A, 4A, 5A, 6A and 7A represent sectional views taken along line A-A of FIG. 2, while FIGS. 3B, 4B, 5B, 6B and 7B represent sectional views taken along line B-B of FIG. 2. Although FIGS. 3A through 7B show one air pump 204, reservoir 208, culvert 210, water valve 220 positioned in culvert 210, air valve 222 and vent shaft 240, other embodiments may employ more than one of these components or may include additional components. Also for the purpose of simplicity, the controller and the driver for operating air pump 203, water valve 220 and air valve 222 are not shown in FIGS. 3A through 7B. Although not shown, additional tugs, rails, towers, pulleys, etc. may be used to assist in moving and stabilizing ship 212 through canal lock 214 of canal lock system 200. It should be readily understood that the reverse of the operation shown in FIGS. 3A through 7B may be used to move ship 212 in the opposite direction through canal lock system 200.

In FIGS. 3A and 3B, gate 232 is opened to allow ship 212 to enter canal lock 214 from channel 230. At this stage the first water level 250 in canal lock 214 is equal to that of channel 230. Gate 234 is closed, and water valve 220 is closed to prevent turbulence which might caused by movement of the water or tidal flow through culvert 210 if allowed to enter to reservoir 208. Air pump 204 is also off and air valve 222 is opened as a safety precaution. At the stage shown in FIGS. 3A and 3B, the pressure inside reservoir 208 is at normal atmospheric pressure.

As also shown in FIGS. 3A and 3B, culvert 210 is connected to bottom 215 of canal lock 214. This allows water from reservoir 208 to enter through bottom 215 of canal lock 214 to thus minimize the disturbance imparted to ship 212 when changing water levels in canal lock 214. As also shown in FIGS. 3A and 3B, reservoir 208 may be located underground and may be reinforced using concrete, metal, etc. Air pump 204 is shown sitting above ground with a tube 242 connecting air pump 204 to reservoir 208. Check valve 244 may be used to control the opening and closing of tube 242.

At the stage shown in FIGS. 3A and 3B, first water level 250 in canal lock 214 will also be equal to the water level lower channel 230. Thus evaporation or water loss from reservoir 208 will not impact the ability of the embodiments of the present invention to raise the water level 250 in canal lock 214. In addition, in some embodiments, when reservoir 208 is of sufficient size to absorb the disturbances caused by ship movement or tidal flow, water valve 220 may be optional or eliminated.

Once ship 212 completely passes through gate 230, gate 230 is shut, as shown in FIGS. 4A and 4B. Water valve 220 is opened, and air valve 222 is closed to create an air tight seal inside reservoir 208. Check valve 244 is also opened, and air pump 204 is turned on to begin pressurizing air into reservoir 208 through tube 242.

As the air is pressurized into reservoir 208, water from reservoir 208 is forced through culvert 210 and into canal lock 214, as shown in FIGS. 5A and 5B. This will result in changing the first water level 250 to a higher second water level 250′, thereby elevating ship 212. Water valve 220 remains open while air valve 222 remains shut. Air pump 204 may continue operating to maintain the air pressure in reservoir 208. Alternatively, check valve 244 may be closed to maintain air pressure in reservoir 208, thereby allowing air pump 204 to be shut off.

As shown in FIGS. 6A and 6B, after ship 212 is raised to second water level 250′, gate 232 is opened to allow ship to pass into canal lock 216. When gate 232 is opened, gate 230 remains closed. Water valve 220 is also closed to prevent any movement of water in canal lock 216 from entering reservoir 208. Check valve 244 is closed.

As shown in FIGS. 7A and 7B, once gate 232 closes so that ship 212 is in canal lock 216 and out of canal lock 214, air vent 222 is opened to depressurize reservoir 208 to thereby receive water from canal lock 214 connected to reservoir 208 (via culvert 210). After air vent 222 is opened, water valve 220 is opened to allow water from canal lock 214 to thereby recirculate (via culvert 210) into reservoir 208. Once second water level 250′ in canal lock 214 is lowered and returns to that of first water level 250, water valve 220 may be closed and the process may be repeated, when required or needed. Ship 212 in canal lock 216 may continue through gate 236 using a similar process until ship 212 is within elevated channel 238. In addition, a flight of locks, such as series of canal locks 214 and 216, may be used to elevate ship 212 from lower channel 230 to elevated channel 238.

Embodiments of the present invention may be advantageous over conventional canal locks and systems since gravity is not used to fill the lower locks with water from an elevated source. Thus, water is not wasted. Further, contamination and species interchange is reduced. Also, no water pumps are used to recirculate the water, which reduces costs and maintenance.

All documents, patents, journal articles and other materials cited in the present application are hereby incorporated by reference.

Although the present invention has been fully described in conjunction with several embodiments thereof with reference to the accompanying drawings, it is to be understood that various changes and modifications may be apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims, unless they depart therefrom. 

1. A canal lock system comprising: at least one canal lock having a bottom and a first water level; at least one reservoir for holding recirculated water connected to the bottom of the at least one canal lock; and at least one air pump connected to the at least one reservoir for pressurizing the at least one reservoir with air to force the water into the at least one lock to thereby change the first water level in the at least one canal lock to a higher second water level, wherein the at least one reservoir maintains a constant volume and wherein the at least one reservoir is depressurized to receive the water from the at least one lock to thereby change the second water level to a lower third water level.
 2. The canal lock system of claim 1, further comprising at least one culvert for connecting the at least one reservoir to the bottom of the at least one canal lock.
 3. The canal lock system of claim 2, further comprising at least one water valve positioned in the at least one culvert for controlling the flow water between the at least one canal lock and the at least one reservoir.
 4. The canal lock system of claim 2, wherein the at least one culvert is connected to the bottom of the at least one canal lock.
 5. The canal lock system of claim 1, further comprising at least one vent for the at least one reservoir to thereby depressurize the at least one reservoir.
 6. The canal lock system of claim 5, wherein the at least one vent comprises at least one vent shaft connected to the at least one reservoir, and at least one air valve for opening and closing the at least one vent shaft.
 7. The canal lock system of claim 1, wherein the third water level is the same as the first level.
 8. The canal lock system of claim 1, wherein a ship is raised in the at least one canal lock when the first water level is changed to the second water level, and wherein the ship is lowered in the at least one canal lock when the second water level is changed to third water level.
 9. The canal lock system of claim 1, wherein the at least one canal lock comprises a flight of canal locks.
 10. The canal lock system of claim 1, wherein the at least one reservoir is underground.
 11. A canal lock system comprising: at least one canal lock; at least one reservoir that holds recirculated water; means for pressurizing the at least one reservoir with air to force the water into the at least one canal lock to thereby change a first water level to a higher second water level in the at least one lock; and means for recirculating the water from the at least one canal lock to the at least one reservoir to thereby change the second water level to a lower third water level, wherein the at least one reservoir maintains a constant volume.
 12. The system of claim 11, wherein the recirculating means comprises means for depressurizing the at least one reservoir.
 13. The system of claim 11, further comprising means for confining a ship in the at least one canal lock when the first water level is changed to the second water level to thereby raise the ship from the first water level to a second water level or when the second water level is changed to the third water level to thereby lower the ship.
 14. The system of claim 11, wherein the recirculating means comprises a culvert connecting the at least one canal lock to the at least one reservoir and wherein the system further comprises means for controlling the flow of water in the culvert.
 15. The system of claim 14, wherein the at least one canal lock has a bottom, wherein the at least one reservoir is underground and wherein the culvert connects the at least one reservoir to the bottom of the at least one canal lock.
 16. A method for operating a canal lock system comprising the following steps: pressurizing at least one reservoir that holds recirculating water with air to force the water into at least one canal lock to thereby change a first water level to a higher second level in the at least one lock; and recirculating the water from the at least one canal lock to the at least one reservoir to thereby change the second water level to a lower third water level, wherein the at least one reservoir maintains a constant volume.
 17. The method of claim 16, comprising the further step of opening a valve to thereby allow the water in the at least one reservoir to be forced into the at least one canal lock.
 18. The method of claim 16, comprising the further step of opening a vent shaft valve to depressurize the at least one reservoir to thereby allow water in the at least one lock to recirculate to the at least one reservoir.
 19. The method of claim 16, comprising the further step of confining a ship in the at least one canal lock, wherein the ship is raised from the first water level to the second water level when the reservoir is pressurized , and wherein the ship is lowered from the second water level to the third water level when the reservoir is depressurized.
 20. The method of claim 16, wherein the at least one canal lock has a bottom and wherein the at least one reservoir is underground and is connected by a culvert to the bottom of the at least one canal lock. 